Packaging material

ABSTRACT

An embodiment of the present invention provides a packaging material including a bag body formed of a sheet in which to house a packaging target and a filter disposed at a vent of the bag body. The filter includes a porous film that is so disposed as to seal up the vent and prevents the entry of water and dust while permitting the passage of the air, and a dehumidification layer that is formed inside the porous film in such a manner as to cover the whole surface of the porous film and absorbs moisture that passes through the porous film to enter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a packaging material used for packaging of precision equipment or the like.

2. Description of the Related Art

Precision equipment such as a laser oscillator used for manufacturing of a semiconductor device is manufactured with extremely-high accuracy. Therefore, there is a fear that it becomes incapable of exerting expected performance if it receives a shock or dust and dirt or the like adheres thereto in transportation. In general, precision equipment is protected in transportation by packaging it by a plastic sheet, a shock absorbing material, etc. and then housing it in a transportation container such as a wooden box or a cardboard box.

However, if precision equipment is packaged by a packaging material such as a plastic sheet with high airtightness and is transported by a method such as air transportation, the packaging material will be broken because of an air pressure difference generated between the inside and outside of the packaging material. Although opening a hole in the packaging material to prevent the breakage because of the air pressure difference may be one countermeasure, this method cannot completely prevent adhesion of dust and dirt to the precision equipment. So, studies are being made on a configuration in which a filter by a porous film (refer to e.g. Japanese Patent Laid-open No. 2009-78866) is attached to a vent of a packaging material to alleviate the air pressure difference generated between the inside and outside of the packaging material with prevention of adhesion of dust and dirt.

SUMMARY OF THE INVENTION

The above-described precision equipment is frequently susceptible to moisture. For example, possibly trouble is caused by a slight temperature rise in a laser oscillator used for manufacturing of a semiconductor device. The above-described filter by a porous film permits the passage of water vapor as well as the air and therefore is not effective for the purpose of preventing moisture in transportation.

It is therefore an object of the present invention to provide a packaging material capable of properly preventing moisture in transportation.

In accordance with an aspect of the present invention, there is provided a packaging material including a bag body formed of a sheet that is hermetically sealed in packaging and houses a packaging target, a vent formed in the bag body in order to make ventilation between the inside and outside of the bag body when the packaging target is packaged, and a filter disposed at the vent. The filter includes a porous film that is so disposed as to seal up the vent and prevents the entry of water and dust while permitting the passage of the air, and a dehumidification layer that is formed inside the porous film in such a manner as to cover the whole surface of the porous film and absorbs moisture that passes through the porous film to enter.

According to this configuration, the filter including the porous film that permits the passage of the air and prevents the entry of water (liquid) and dust and the dehumidification layer to absorb moisture (gas, water vapor) that passes through the porous film to enter is provided at the vent of the bag body in which to house the packaging target. This can prevent the entry of water and dust into the inside of the bag body and the entry of moisture. Thus, increase in the humidity inside the bag body can be prevented. According to the present invention, a packaging material capable of properly preventing moisture in transportation can be provided.

The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the whole configuration of a packaging material according to the present embodiment;

FIG. 2 is a sectional schematic diagram showing a configuration example of a filter used for the packaging material according to the present embodiment; and

FIG. 3 is a sectional schematic diagram showing a modification example of the filter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will be described below with reference to the accompanying drawings. In the following, an example of a packaging material used for packaging of precision equipment such as a laser oscillator will be shown. However, the use purpose of the packaging material according to the present invention is not particularly limited. FIG. 1 is a schematic diagram showing the whole configuration of a packaging material according to the present embodiment. In FIG. 1, a packaging material 1 to package a packaging target 2 such as a laser oscillator is shown. As shown in FIG. 1, the packaging material 1 includes a bag body 11 that wraps the packaging target 2 having a substantially rectangular parallelepiped shape and a filter 12 attached to the bag body 11. The shape of the packaging target 2 is not particularly limited and may be a spherical shape, a plate shape, etc.

The bag body 11 is an object obtained by processing a sheet (film) composed of a synthetic resin such as polyvinyl chloride or polyethylene into a bag shape and is so formed as not to permit the passage of water and oil (liquid), the air and water vapor (gas), and so forth in addition to dust and dirt. In packaging of the packaging target 2, the packaging target 2 is inserted into the bag body 11 from a mouth part (not shown) of the bag body 11 and this mouth part is closed by a method such as heat sealing (thermal sealing). By hermetically sealing the bag body 11 with the packaging target 2 wrapped in this manner, adhesion of dust, dirt, water, oil, and so forth to the packaging target 2 can be prevented.

FIG. 2 is a sectional schematic diagram showing a configuration example of the filter used for the packaging material according to the present embodiment. As shown in FIGS. 1 and 2, the filter 12 includes a cylindrical chassis 121 having opening parts 121 a and 121 b at both end parts. The chassis 121 is so formed as not to permit the passage of dust and dirt, water and oil (liquid), the air and water vapor (gas), and so forth similarly to the bag body 11. The chassis 121 is fixed to a vent 111 of the bag body 11 in such a manner that the opening part 121 a on one end side is exposed to the outside of the bag body 11 and the opening part 121 b on the other end side is positioned inside the bag body 11. An outer circumferential part 121 c of the chassis 121 is bonded to the inner circumferential part of the vent 111 without a gap.

As shown in FIG. 2, at the opening part 121 a of the chassis 121, a porous film 122 that seals up the opening part 121 a is provided. The porous film 122 is a film (sheet) having minute holes that permit the passage of the air and water vapor (gas) and so forth and do not permit the passage of water and oil (liquid), dust and dirt (solid), and so forth. As such a porous film 122, e.g. a film formed of a fluorine resin such as PTFE (polytetrafluoroethylene), polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, or tetrafluoroethylene-ethylene copolymer can be used.

As described above, the opening part 121 a of the filter 12 is sealed up by the porous film 122. Thus, dust and dirt (solid), water and oil (liquid), and so forth do not enter the inside of the bag body 11 through the filter 12. Meanwhile, the porous film 122 permits the passage of the gas. Therefore, although the bag body 11 is hermetically sealed, the air comes and goes through the filter 12 and the air pressure difference between the inside and outside of the bag body 11 is alleviated. Consequently, the breakage of the packaging material 1 attributed to the air pressure difference in transportation can be prevented.

By the way, water (moisture and water vapor) in the air passes through the porous film together with the air to enter the inside of the bag body. Therefore, in the case of using the packaging material having the filter formed with the porous film, a problem occurs in transportation of a packaging target susceptible to moisture. For example, possibly trouble is caused by a slight humidity rise in a laser oscillator or the like used for manufacturing of a semiconductor device. So, in the packaging material 1 according to the present embodiment, a dehumidification layer 123 is disposed in the flow path of the air that passes through the porous film 122 of the filter 12 and flows into the bag body 11.

A net 124 that permits the passage of the air is provided at the opening part 121 b of the chassis 121. In the region sandwiched by the porous film 122 and the net 124 in the chassis 121, the dehumidification layer 123 by a desiccant such as silica gel is disposed. Specifically, the dehumidification layer 123 is so formed as to cover the whole surfaces of the porous film 122 and the net 124. The mesh of the net 124 is so fine that the dehumidification layer 123 does not drop out from the chassis 121.

As shown by an arrow A in FIG. 2, the air that has passed through the porous film 122 is supplied to the inside of the bag body 11 through the dehumidification layer 123 in the chassis 121. At this time, moisture in the air is removed by the dehumidification layer 123 and therefore sufficiently-dried air flows into the inside of the bag body 11. As a result, the humidity in the bag body 11 is kept sufficiently low. In the case of a configuration in which a desiccant is disposed at an arbitrary position inside the bag body 11, there is a fear that the humidity locally increases around the vent 111. However, the configuration of the present embodiment is free from such an anxiety because the air flowing into the inside of the bag body 11 is surely dehumidified by the dehumidification layer 123.

The chassis 121 has a predetermined height (equivalent to the distance from the opening part 121 a to the opening part 121 b) so that the flow path of the air flowing in the chassis 121 may be sufficiently long. Therefore, the air that has flowed into the chassis 121 through the porous film 122 is properly dehumidified during flowing in the chassis 121. Furthermore, the wall part of the chassis 121 is so formed as not to permit the passage of the air. Therefore, an air flow like that shown by an arrow B in FIG. 2 does not occur. Thus, the air that has flowed into the chassis 121 through the porous film 122 can be properly dehumidified by the dehumidification layer 123.

As above, in the packaging material 1 according to the present embodiment, the filter 12 including the porous film 122 that permits the passage of the air and prevents the entry of water (liquid) and dust and the dehumidification layer 123 to absorb moisture (gas, water vapor) that passes through the porous film 122 to enter is provided at the vent 111 of the bag body 11 in which to house the packaging target 2. This can prevent the entry of water (liquid) and dust into the inside of the bag body 11 and the entry of (water vapor). Thus, increase in the humidity inside the bag body 11 can be prevented.

The present invention is not limited to the description of the above embodiment and can be carried out with various changes. For example, a filter including two porous films may be applied to a packaging material in order to prevent adhesion of dust and dirt to a packaging target more properly. FIG. 3 is a sectional schematic diagram showing a modification example of the filter. A filter 13 shown in FIG. 3 includes a cylindrical chassis 131 having opening parts 131 a and 131 b at both end parts.

At the opening part 131 a of the chassis 131, a porous film 132 that seals up the opening part 131 a is provided. At the opening part 131 b of the chassis 131, a porous film 134 that seals up the opening part 131 b is provided. In the chassis 131, a dehumidification layer 133 is disposed in the region sandwiched by the porous films 132 and 134. That is, the filter 13 according to the modification example has a configuration obtained by replacing the net 124 of the filter 12 of the above-described embodiment by the porous film 134. Because this filter 13 has the porous films 132 and 134 at both end parts of the chassis 131, it can prevent the entry of dust, dirt, and so forth into the bag body 11 more properly by the two porous films.

Although the packaging material in which the filter having the porous film and the dehumidification layer is provided for the bag body is shown in the above embodiment, the configuration of the packaging material is not limited thereto. For example, a packaging material may be made by attaching the filter to a hard case that is composed of plastic, metal, or the like and has airtightness instead of the bag body.

Although the packaging material including one filter is exemplified in the above embodiment, the number of filters may be any. Furthermore, although the filter having the cylindrical chassis is exemplified in the above embodiment, the shape of the filter is also not limited. However, to realize proper dehumidification, it is desirable to employ a shape having a sufficient height. Moreover, a removable seal having no air permeability may be attached to the front side of the porous film and the net (opposite side to the dehumidification layer) and the seal may be removed in use. In this configuration, the deterioration of the dehumidification layer before use can be prevented.

The present invention is not limited to the details of the above described preferred embodiment. The scope of the invention is defined by the appended claims and all changes and modifications as fall within the equivalence of the scope of the claims are therefore to be embraced by the invention. 

1. A packaging material comprising: a bag body formed of a sheet that is hermetically sealed in packaging and houses a packaging target; a vent formed in the bag body in order to make ventilation between inside and outside of the bag body when the packaging target is packaged; and a filter disposed at the vent, wherein the filter includes a porous film that is so disposed as to seal up the vent and prevent entry of water and dust while permitting passage of air, and a dehumidification layer that is formed inside the porous film in such a manner as to cover a whole surface of the porous film and absorb moisture that passes through the porous film to enter, and wherein the air comes and goes through the filter, so that the air pressure difference between the inside and outside of the bag body is alleviated.
 2. The packaging material of claim 1, wherein the filter further includes a chassis having a first opening part on one end side that is exposed to the outside of the bag body and a second opening part on the other end side positioned inside the bag body, the porous film being at the first opening part, the chassis further having a net at the second opening part, the net permitting the passage of air, the dehumidification layer being between the porous film and the net.
 3. The packaging material of claim 1, wherein the filter further includes a chassis having a first opening part on one end side that is exposed to the outside of the bag body and a second opening part on the other end side positioned inside the bag body, the porous film being at the first opening part, the chassis further having a second porous film at the second opening part, the second porous film permitting the passage of air, the dehumidification layer being between the porous film and the second porous film. 